Patent Document 1 discloses a thermoplastic elastomer that includes an elastomeric polymer, the elastomeric polymer including a side chain that includes a hydrogen bond-crosslinkable moiety that includes a carbonyl-containing group and a nitrogen-containing heterocyclic ring, and a side chain that includes a covalent bond-crosslinkable moiety, the elastomeric polymer having a glass transition temperature (Tg) of 25° C. or less. The elastomeric polymer can be crosslinked in the covalent bond-crosslinkable moiety via an amide bond, an ester bond, a lactone bond, a urethane bond, an ether bond, a thiourethane bond, or a thioether bond. The main chain of the elastomeric polymer includes a diene-based rubber, an olefin-based rubber, a (hydrogenated) polystyrene-based elastomeric polymer, a polyolefin-based elastomeric polymer, a polyvinyl chloride-based elastomeric polymer, a polyurethane-based elastomeric polymer, a polyester-based elastomeric polymer, or a polyamide-based elastomeric polymer. Patent Document 1 discloses that the thermoplastic elastomer is obtained by reacting a compound that can introduce a nitrogen-containing heterocyclic ring with a side-chain cyclic acid anhydride group of an elastomeric polymer, and discloses that the nitrogen-containing heterocyclic ring introduced by the above reaction and a carbonyl-containing group derived from the cyclic acid anhydride group that is ring-opened by the above reaction form the hydrogen bond-crosslinkable moiety, and the cyclic acid anhydride group that remains unreacted forms the covalent bond-crosslinkable moiety. Patent Document 1 states that the thermoplastic elastomer has excellent recyclability, and exhibits excellent mechanical strength.